LBL is proposing the construction of a dedicated biomedical center for intensive development of heavy charged-particle techniques for clinical use. We anticipate the construction to start within the next five years. This center will emphasize research with both protons and heavier ions. The rationale of a strong proton component of our program lies with intercomparison of low and high LET irradiations, and technology transfer of hardware and techniques developed for hospital-based clinical proton facilities to be built worldwide in the near future. Specifically we will: (1) Study the technical elements needed for designing an integrated, efficient, reliable and cost-effective proton treatment facility. Optimize accelerator designs, beam spreading techniques, gantries, control systems, and systems-integration. Analyze applicability of new ideas (e.g. rapid- pulsing systems) and emerging technologies (e.g. superconductivity). (2) Investigate ways to utilize the best characteristics of proton beams for treatment of human diseases. Study 3-D conformal treatment techniques, their expected clinical benefits, interfacing treatment plans with beam delivery system, and the merits of correlating multiple imaging modalities. Using the particle beams from the Vevalac and the LBL dynamic beam delivery system, assess the performance of a 3-dimensional conformal therapy delivery system. (3) Identify disease sites that would most benefit from proton therapy and develop protocols for these sites. Identify areas where radiobiological input is critical for aid in interpretation of clinical results. Select protocols for which equitable intercomparison can be made of the clinical benefits of protons (low LEt) and heavier ions (high LET). The results of the project will provide timely input to the scientific and medical community which is witnessing a significant transfer of advanced technology of heavy charged-particle medicine from research institutions into the clinical environment.